In-circuit test fixture loader

ABSTRACT

An in-circuit test fixture loader includes a carrier that is able to receive and support an in-circuit test fixture. The carrier includes a pair of opposing side rails and an end rail between the side rails. The side rails and the end rail are spaced to receive the in-circuit test fixture between the side rails and against the end rail. The loader also includes a fixture lock connected to the carrier to prevent movement of the in-circuit test fixture away from the end rail. A horizontal slider attached between the carrier and a mechanism base includes guide shafts that guide the carrier and the in-circuit test fixture in a first substantially horizontal direction. A vertical slider of the loader is attached between the carrier and the mechanism base. The vertical slider includes an actuator that is operable to slide the carrier and the in-circuit test fixture in a second substantially vertical direction between an upper position and a lower position. The horizontal slider and the vertical slider are able to guide the in-circuit test fixture and the carrier between a receive position, wherein the in-circuit test fixture may be loaded on the carrier, and a test position, wherein a printed circuit board assembly supported by the in-circuit test fixture may be tested. Also, a clamp mounted on a testing base is able to selectively secure the in-circuit test fixture to the testing base in the test position.

RELATED APPLICATIONS

[0001] This application claims priority of U.S. provisional application Serial No. 60/364,775, filed Mar. 15, 2002.

FIELD OF THE INVENTION

[0002] This application relates generally to in-circuit testing and more particularly to an in-circuit test fixture loader.

BACKGROUND OF THE INVENTION

[0003] Testing of disc drive printed circuit board assemblies is done to ascertain the operational integrity of the circuit board components. For in-circuit test systems, an in-circuit test fixture supports the printed circuit board being tested. Additionally, the fixture serves as an electrical and/or mechanical interface between the circuit board assembly testing nodes and the required test instruments.

[0004] Automated in-circuit test systems have been developed to more efficiently test printed circuit board assemblies. However, even in automated systems the fixtures have typically been manually loaded into the test system. Such fixtures can be difficult to load into the system, especially in “horizontal receiver access” test systems where the fixture must be inserted horizontally through an opening in the test system.

[0005] As an example, in one test system for testing disc drive printed circuit board assemblies, the fixture includes separable base plate and top plate assemblies, weighing about 18 kg and 10 kg, respectively. The base plate assembly of the system is especially difficult to load. Factors contributing to this difficulty include: (1) the weight of the base assembly (about 18 kg); (2) the structure of the base assembly (offset and elongated), (3) limited access for gripping the assembly by hand; (4) awkward loading position that is partially blocked by structural members of the test system; and (5) the fixture wiring, which typically includes more than 1000 wire connections. Loading such a fixture into the test system can result in the base plate assembly impacting portions of the testing system structure, which in turn results in damage to the base assembly, wiring damage, or possibly even injury to the operator.

[0006] Accordingly there is a need for a safer and more reliable way to load fixtures for automated in-circuit test systems. The present invention provides a solution to this and other problems, and offers other advantages over the prior art.

SUMMARY OF THE INVENTION

[0007] Against this backdrop the present invention has been developed. An in-circuit test fixture loader according to an embodiment of the present invention includes a carrier that is able to receive and support an in-circuit test fixture. The carrier includes a pair of opposing side rails and an end rail between the side rails. The side rails and the end rail are spaced to receive the in-circuit test fixture between the side rails and against the end rail. The loader also includes a fixture lock connected to the carrier. The fixture lock is able to selectively abut the in-circuit test fixture to prevent movement of the in-circuit test fixture away from the end rail. A horizontal slider attached between the carrier and a mechanism base includes guide shafts on opposite sides of the carrier that guide the carrier and the in-circuit test fixture in a first substantially horizontal direction. A vertical slider of the loader is also attached between the carrier and the mechanism base. The vertical slider includes an actuator that is operable to slide the carrier and the in-circuit test fixture in a second substantially vertical direction between an upper position and a lower position. The horizontal slider and the vertical slider are operable to guide the in-circuit test fixture and the carrier between a receive position, wherein the in-circuit test fixture may be loaded on the carrier, and a test position, wherein a printed circuit board assembly supported by the in-circuit test fixture may be tested. Also, a clamp mounted on a testing base is able to selectively secure the in-circuit test fixture to the testing base in the test position.

[0008] A method of loading an in-circuit test fixture in an in-circuit test system according to an embodiment of the present invention includes sliding the in-circuit test fixture between side rails of a carrier until the in-circuit test fixture abuts and end rail of the carrier when the carrier is in a receive position, and locking the in-circuit test fixture to the carrier by preventing the in-circuit test fixture from moving away from the end rail. The method further includes sliding the carrier and the in-circuit test fixture along horizontal guide shafts in a first horizontal direction from the receive position to a match position, and actuating a vertical slider connected to the carrier to slide the in-circuit test fixture along vertical guide shafts in a second vertical direction from the match position to a test position. Finally, the method includes clamping the in-circuit test fixture in the test position.

[0009] These and various other features as well as advantages which characterize the present invention will be apparent from a reading of the following detailed description and a review of the associated drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0010]FIG. 1 is a plan view of a disc drive showing the primary internal components.

[0011]FIG. 2 is a rear perspective view of an in-circuit test fixture loader according to a preferred embodiment of the present invention before the fixture is positioned on the loader.

[0012]FIG. 3 is a separate perspective view of one side of the horizontal slider shown in FIG. 2.

[0013]FIG. 4 is a separate perspective view of the vertical slider shown in FIG. 2.

[0014]FIG. 5 is a separate perspective view of the clamp assembly shown in FIG. 2.

[0015]FIG. 6 is a front perspective view of the loader of FIG. 2 with a fixture loaded in the test position showing the proximity sensors in the loader.

[0016]FIG. 7 is a process flow chart of a method of fixture loading according to a preferred embodiment of the present invention.

[0017]FIG. 8 is a rear perspective view of the loader of FIG. 2 with the fixture positioned on the tray in the receive position and the fixture locks in the unlock position.

[0018]FIG. 9 is a rear perspective view of the loader of FIG. 2 with the fixture positioned on the tray in the receive position and the fixture locks in the lock position.

[0019]FIG. 10 is a rear perspective view of the loader of FIG. 2 with the fixture in the match position.

[0020]FIG. 11 is a rear perspective view of the loader of FIG. 2 with the fixture clamped in the test position.

DETAILED DESCRIPTION

[0021] A disc drive 100 constructed in accordance with a preferred embodiment of the present invention is shown in FIG. 1. The disc drive 100 includes a base 102 to which various components of the disc drive 100 are mounted. A top cover 104, shown partially cut away, cooperates with the base 102 to form an internal, sealed environment for the disc drive in a conventional manner. The components include a spindle motor 106, which rotates one or more discs 108 at a constant high speed. Information is written to and read from tracks on the discs 108 through the use of an actuator assembly 110, which rotates during a seek operation about a bearing shaft assembly 112 positioned adjacent the discs 108. The actuator assembly 110 includes a plurality of actuator arms 114 which extend towards the discs 108, with one or more flexures 116 extending from each of the actuator arms 114. Mounted at the distal end of each of the flexures 116 is a head 118, which includes an air bearing slider, enabling the head 118 to fly in close proximity above the corresponding surface of the associated disc 108.

[0022] During a seek operation, the track position of the heads 118 is controlled through the use of a voice coil motor 124, which typically includes a coil 126 attached to the actuator assembly 110, as well as one or more permanent magnets 128 which establish a magnetic field in which the coil 126 is immersed. The controlled application of current to the coil 126 causes magnetic interaction between the permanent magnets 128 and the coil 126 so that the coil 126 moves in accordance with the well-known Lorentz relationship. As the coil 126 moves, the actuator assembly 110 pivots about the bearing shaft assembly 112, and the heads 118 are caused to move across the surfaces of the discs 108.

[0023] The spindle motor 106 is typically de-energized when the disc drive 100 is not in use for extended periods of time. The heads 118 are moved over park zones 120 near the inner diameter of the discs 108 when the drive motor is de-energized. The heads 118 are secured over the park zones 120 through the use of an actuator latch arrangement, which prevents inadvertent rotation of the actuator assembly 110 when the heads are parked.

[0024] A flex assembly 130 provides the requisite electrical connection paths for the actuator assembly 110 while allowing pivotal movement of the actuator assembly 110 during operation. The flex assembly includes a printed circuit board 132 to which head wires (not shown) are connected; the head wires being routed along the actuator arms 114 and the flexures 116 to the heads 118. The printed circuit board 132 typically includes circuitry for controlling the write currents applied to the heads 118 during a write operation and a preamplifier for amplifying read signals generated by the heads 118 during a read operation. The flex assembly terminates at a flex bracket 134 for communication through the base deck 102 to a disc drive printed circuit board (not shown) mounted to the bottom side of the disc drive 100.

[0025] Testing of disc drive printed circuit board assemblies is done to ascertain the operational integrity of the circuit board components. FIG. 2 illustrates a loader 210 for loading an in-circuit test fixture 212 into an in-circuit test system. The fixture 212 preferably supports a printed circuit board assembly to be tested in the in-circuit test system. The loader 210 includes a tray or carrier 214 and a mechanism 215 that facilitates movement of the tray 214 in a horizontal direction and in a vertical direction. More specifically, the mechanism 215 has a horizontal slider assembly 216 that facilitates horizontal movement of the tray 214, and a vertical slider or slider assembly 218 facilitates vertical movement of the tray 214. The mechanism 215 is secured to a loader base 220 that is attached to the remainder of the in-circuit test system (not shown). A clamp assembly 222 is attached to a testing base 224.

[0026] Basically, a user positions the fixture 212 on the tray 214. The user then slides the tray 214 forward, as allowed by the horizontal slider assembly 216, so that the fixture 212 is positioned above the clamp assembly 222. The user then slides the tray downward, preferably by activating an actuator of the vertical slider assembly 218. The clamp assembly 222 then clamps the fixture 212 so that it is stationary relative to the testing base 224. The fixture 212 is then fully loaded and a circuit board assembly or another circuit unit within the fixture can be tested by the test system.

[0027] When it is desirable to remove the fixture 212, such as when a manufacturing line has completed testing of a required number of printed circuit board assemblies, the clamp assembly 222 releases the fixture 212. The tray 214 and the fixture 212 are then moved up, preferably via actuation of an actuator of the vertical slider assembly 218. The tray 214 and the fixture 212 are then slid backward, as allowed by the horizontal slider assembly 216. The fixture 212 is then removed from the tray 214. Thus, the loader 210 allows a user to load and unload the fixture 212 without requiring the user to support the weight of the fixture 212 while moving the fixture 212 forward and down into the in-circuit test system.

[0028] The loader 210 will now be described in more detail with reference to FIG. 2. The in-circuit test fixture 212, which is illustrated in simplified form, may be an entire in-circuit test fixture or only a part of the in-circuit test fixture, such as a base plate assembly or a top plate assembly of an in-circuit test fixture. The fixture 212 includes a body 230, which is illustrated as substantially rectangular in shape. In the case of disc drive printed circuit board testing, for example, the fixture 212 may simply be represented as a box-shaped housing receiving and supporting a disc drive circuit board assembly so that the disc drive printed circuit board is exposed to the testing system. The body 230 includes a bottom surface 232 and an opposing top surface 234. Fixture ears or plates 236 extend along opposing sides of the body 230. Each ear 236 defines a pair of clamp receiving holes 238, with one clamp-receiving hole 238 extending vertically through the front portion of each ear 236 and one clamp-receiving hole 238 extending vertically through the rear portion of each ear 236.

[0029] The tray 214 includes a pair of side rails 250 that extend backward from opposing ends of a front or end rail 252. Tracks 254 extend inwardly from the lower edge of each side rail 250 so that each side rail 250 and track 254 forms a substantially L-shaped cross section. Rollers 256 extend inwardly from each side rail 250 along an upwardly facing surface of each track 254. In a preferred embodiment of the present invention, the rollers 256 each protrude about 0.5 mm above the upper surface of each track 254 and are spaced at about 30 mm intervals along each track 254. The rear of each side rail 250 is raised and defines mounting holes 258 therein.

[0030] A handlebar 262, which is preferably an elongate plate, extends between the bottom rear of each track 254. The handlebar 262 defines a pair of gripping holes 264. Each hole 264 is preferably sized and shaped to receive an average size set of human fingers.

[0031] Referring now to FIGS. 2-3, the horizontal slider assembly 216 includes a pair of carriages 270 on opposite sides of the tray 214. Each carriage 270 has a substantially rectangular shaped body 272 that defines a pair of guide shaft holes 274 that extend horizontally through the body 272, and a set of mounting holes 276 that extend normal to the guide shaft holes 274 and into the body 272. The mounting holes 276 of each carriage 270 align with the mounting holes 258 in the tray 214 and receive fasteners, such as screws that secure the tray 214 to the carriages 270.

[0032] Each carriage 270 also includes a pair of carriage ears 278 that extend up from the front and rear of the carriage body 272. Each ear 278 has a fixture lock hole 294 therethrough that is substantially parallel to the guide shaft holes 274. A flip-over fixture lock 296 is seated between each set of carriage ears 278 and a pin (not shown) extends through the fixture lock holes 294 and through the fixture lock 296. Each fixture lock 296 is preferably an elongate member that extends away from the carriage 270. The fixture locks 296 can rotate about the pin between an unlock position shown in FIGS. 2 and 8, where the fixture locks 296 extend outwardly from the carriages 270, and a lock position shown in FIGS. 9-11, where the fixture locks extend inwardly from the carriages 270. The fixture locks 296 are preferably held in each position by gravity or may be spring biased in each of the unlocked and locked positions.

[0033] Each side of the horizontal slider assembly 216 has a side frame member 280 outwardly from the carriages 270 as shown in FIG. 3. The horizontal slider frame members 280 are substantially parallel to the side rails 250 of the tray 214, but are on opposite sides of the carriages 270 so that each carriage 270 is positioned between a horizontal slider frame member 280 and a side rail 250 of the tray 214. A horizontal slider support plate 282 extends between the bottom of the horizontal slider frame members 280 and fixes the horizontal frame members 280 together (see FIGS. 10-11). Two support walls 284 extend inwardly at right angles from the ends of each slider frame member 280. A lower and an upper guide shaft 286 extend along the frame members 280 between each set of support walls 284. Each guide shaft 286 extends through a guide shaft hole 274 in a carriage 270 and supports the carriage 270 for sliding movement forward and backward along the guide shafts 286. Preferably, the carriages 270 include linear bearings that allow the carriages to easily slide along the guide shafts 286. In a preferred embodiment, the carriages 270 each include DU Bearings available under part number NB-1625DU from Daido Metal Co. Ltd. of Nagoya, Japan.

[0034] Two spring loaded tray locks 298, shown in FIG. 2, are seated in the horizontal slider support plate 282 inwardly from the rear support walls 284. The tray locks 298 preferably include plungers or pins 299 that are spring loaded so that they are biased upwardly through the horizontal slider support plate 282. The plungers 299 preferably each include a step that they can move upwardly when in one angular position, but not in another angular position. When the tray 214 is located in its rear-most or “receive” position as shown in FIG. 2 and the plungers 299 are rotated so that the steps on the plungers 299 align with arcuate recesses in the tray locks 298, the plungers 299 move up to a lock position engaging apertures (not shown) in the handlebar 262 of the tray 214. When the plungers 299 are pulled down from the lock position to a release position, the tray 214 is released and can move forward. The plungers 299 can be secured in the unlock position by rotating the plungers 299 so that the steps on the plungers 299 no longer align with the arcuate recesses in the tray locks 298. Exemplary tray locks are available under part number MIPL-NDX10LW from Imao Corp. of Gifu, Japan.

[0035]FIGS. 2 and 4 illustrate the vertical slider assembly 218, which is separately shown in FIG. 4. The vertical slider assembly 218 includes a flat, generally U-shaped vertical slider support plate 310 that is part of the mechanism base 220. A pneumatic actuator 312 is secured to each leg of the U-shaped vertical slider support plate 310. Each pneumatic actuator 312 includes a plunger or ram 314 that extends upwardly through the vertical slider support plate 310. The terminus of each ram 314 is secured to a support bar 315 (FIG. 2) that is fixed to the outer side of one of the frame members 280 of the horizontal slider assembly 216. Two guide/alignment shafts 316 extend through the vertical slider support plate 310 toward upper ends that are also secured to the support bars 315 forward and rearward of the ram 314. Each pair of alignment shafts 316 also extends down through the vertical slider support plate 310 to an alignment shaft support bar 318. In this way, alignment shafts 316 are maintained in parallel alignment between the bars 315 and 318. Additionally, referring to FIG. 2, an alignment shaft support unit 320 includes an L-shaped body 322 that is fixed to the mechanism base 220 and to the front alignment shaft 316.

[0036] Referring now to FIGS. 2 and 5, each fixture clamp assembly 222 includes an L-shaped fixture support bracket 340 that has a vertical plate portion 342 and a horizontal plate portion 344 extending inwardly from the top of the vertical plate portion 342. The support brackets 340 are preferably rigidly mounted as part of the testing base 244. Each horizontal plate portion 344 defines a pair of clamp shaft holes 346 that align with the clamp receiving holes 238 in the fixture 212 when the fixture 212 is positioned over the clamp assembly 222 as shown in FIGS. 10-11. Each horizontal plate portion 344 also defines an upwardly facing fixture support surface 348.

[0037] The fixture clamp assembly 222 also includes a pair of L-shaped clamp actuator support brackets 360 that are secured to each vertical plate portion 342 below and parallel to the horizontal plate portion 344. Each clamp actuator support bracket 360 defines a pair of actuator access holes 364 that are aligned with the clamp shaft holes 346 through the horizontal plate portion 344. Two clamp actuators 366 are fastened to each clamp actuator support bracket 360 and include rams 368 that extend upwardly through the actuator access holes 364 and through the clamp shaft holes 346 through the horizontal plate portion 344. The actuators are preferably pneumatic cylindrical actuators, such as those available under part number AC-MKA40-10TL from SMC Corp. of Tokyo, Japan. The actuators 366 also each include an upper reed sensor 370 that senses when the corresponding ram 368 is in its upper-most, or unclamped, position and a lower reed sensor 372 that senses when the corresponding ram 368 is in its lower-most, or clamped, position.

[0038] A clamp 380 is fixed to the upper end of each ram 368. Each clamp 380 includes a cylindrical clamp body 382 seated on a ram 368 and a pair of clamp arms 384 that extend in opposite horizontal directions from the top of the clamp body 382 and then curve downwardly. The clamp actuators 366 each move the ram shafts, and thus the clamps 380 in a spiral motion so that the clamp arms 384 rotate as to extend forwardly and rearward from the clamp body 382 when the rams 368 are in their uppermost or release position (see FIG. 10) and the clamp arms 384 extend ninety degrees to the left and right from the clamp body 382 when the rams 368 are in their lowermost or clamp position (see FIG. 11).

[0039]FIG. 6 illustrates a pair of proximity sensors 390 that extend upwardly and inwardly from the testing base 224 forward from the clamp assembly 222. The proximity sensors 390 activate by sensing the front of the fixture 212 when the fixture 212 is in the match position shown in FIG. 10 or the loaded position shown in FIG. 11. The proximity sensors 390 preferably sense whether the proximity sensors are within about 1 mm of a metallic object. The proximity sensors 390 may be 1 mm proximity switches sold under part number ENP-ESE-X1C1 by Omron, of Kyoto, Japan.

[0040] The various structural components of the loader 210 discussed above are preferably secured together with fasteners, such as screws or bolts. Also, the loader 210 is preferably positioned about one meter above the floor, positioning the loader 210 ergonomically for human handling of a heavy item, such as the in-circuit test fixture 212.

[0041] Use of the loader 210 will now be described with reference to FIG. 7. A user first secures the tray 214 to the mechanism base 220 in lock tray operation 410 by rotating the plungers 299 of the tray locks 298 so that the plungers 299 move up to engage the apertures in the tray 214. The tray 214 is thus locked in the receive position shown in FIG. 2.

[0042] The user then mounts the test fixture 212 onto the tray 214 and slides the in-circuit test fixture 212 along the rollers 256 of the tray 214 in place fixture operation 412. Preferably, the fixture 212 is slid until a front surface of the fixture 212 abuts the end rail 252 of the tray 214, as shown in FIG. 8. The rollers 256 along the tracks 254 then support the fixture 212. The end rail 252 prevents the fixture 212 from sliding farther forward and the side rails 250 prevent the fixture 212 from sliding to either side.

[0043] In lock fixture operation 414, a user rotates the fixture locks 296 180 degrees from the inward horizontal unlock position shown in FIG. 8 to the opposite horizontal lock position shown in FIG. 9. In the lock position of FIG. 9, the fixture locks 296 prevent the fixture 212 from sliding backward on the tray 214. Thus, the combination of the side rails 250, the end rail 252, and the fixture locks 296 secures the fixture 212 on the tray 214.

[0044] The user then pulls each of the plungers 299 down and rotates them to secure them in the unlock position where they are disengaged from the apertures in the tray 214 in unlock tray operation 416. The tray 214 is then free to move forward, which movement is facilitated by the horizontal slider 216. In slide forward operation 420, the user slides the tray 214 and the fixture 212 forward along the rails 286 to the match position illustrated in FIG. 10.

[0045] In match position query operation 422, it is determined whether the fixture 212 is positioned so that the clamp receiving holes 238 are aligned above the clamps 380. This is done by visual inspection and by the proximity sensors 390, which sense whether the fixture 212 is positioned fully forward in the proper match position. In fact, the loader 210 preferably will not proceed to lower the fixture 212 until the proximity sensors 390 detect a fixture in the match position. This prevents the loader 210 from undesirably proceeding if a fixture 212 is not properly positioned on the tray 214 or the tray 214 has not been properly moved to the match position. If the fixture 212 is not in the proper match position, then the user preferably detects the problem and fixes it in inspect and fix operation 424. If the fixture 212 is then in the proper match position as determined in the match position query operation 422, then the user can continue with a lower tray and fixture operation 430.

[0046] In the lower tray and fixture operation 430, the user preferably depresses a button or a pair of buttons to activate the actuators 312 of the vertical slider assembly 218. The actuators 312 move the rams 314 of the vertical slider 218 and in turn move the fixture 212 and the tray 214 down from the match position of FIG. 10 to the test position of FIG. 11. Then, in clamp operation 432, the clamp actuators 366 draw the clamps 380 spirally downwardly so that the clamps 380 secure the fixture ears 236 between the clamp arms 384 and the fixture support surfaces 348 of the fixture support brackets 340.

[0047] In the test position query operation 434, the proximity sensors determine whether the fixture 212 is properly seated fully forward as is proper for the test position. Additionally, the lower reed sensors 372 preferably sense whether the rams 368 are fully retracted, and thus that the clamps 380 are in the clamped position shown in FIG. 11. If the test position query operation 434 determines that the fixture 212 is not properly clamped in the clamp position, then the user preferably detects the problem and fixes it in inspect and fix operation 436. If the fixture 212 is properly clamped in the test position as determined in the test position query operation 434, then the fixture is ready for a circuit or set of circuits, such as a set of circuits in a component of a printed circuit board assembly to be tested. The loader preferably illuminates an indicator light, such as a light within one of the buttons discussed above, or otherwise signals that the fixture is fully loaded and ready for testing. Preferably, the in-circuit test system will not proceed with testing until the test position query operation 434 determines that the fixture 212 is properly clamped in the test position. In test operation 440, the in-circuit test system uses the fixture 212 in testing circuits of circuit board assemblies.

[0048] A remove fixture query operation 441 determines whether it is desirable to remove the fixture 212, for example when a manufacturing line has completed testing of a required number of printed circuit board assemblies or the fixture 212 must be removed to perform repairs or maintenance. When it is desirable to remove the fixtures 212, the fixture 212 is unclamped in unclamp operation 442. In unclamp operation 442, the clamp actuators 366 merely reverse the motion of the clamp operation 432 described above. To perform this operation, the user preferably depresses a button or set of buttons to activate the clamp actuators 366. Alternatively, the loader 210 can automatically unclamp the fixture 212 when testing is complete. In raise tray and fixture operation 444, the actuators 312 of the vertical slider 218 preferably lift the tray 212 and the fixture 214 to the match position shown in FIG. 10.

[0049] Once the raise tray and fixture operation 444 is complete, the user grasps the gripping holes 264 of the handlebar 262 and pulls the tray 212 and the fixture 214 backward to the receive position shown in FIG. 9. The horizontal slider 216 facilitates this movement. The user then rotates the plungers 299, allowing them to be biased upwardly to engage the tray 214 in lock tray operation 450. The user then pivots the fixture locks 296 from the locked position shown in FIG. 9 to the unlocked position shown in FIG. 8 during unlock fixture operation 452, freeing the fixture 212 to slide backward. The user pulls the fixture 212 out of the tray 214 along the rollers 256 in remove fixture operation 454.

[0050] An embodiment of the present invention may be summarized as an in-circuit test fixture loader (such as 210). The loader includes a carrier (such as 214) that is able to receive and support an in-circuit test fixture (such as 212). The carrier includes a pair of opposing side rails (such as 250) and an end rail (such as 252) between the side rails. The side rails and the end rail are spaced to receive the in-circuit test fixture between the side rails and against the end rail. The loader also includes a fixture lock (such as 296) connected to the carrier. The fixture lock is able to selectively abut the in-circuit test fixture to prevent movement of the in-circuit test fixture away from the end rail. A horizontal slider (such as 216) attached between the carrier and a mechanism base (such as 220) includes guide shafts (such as 286) on opposite sides of the carrier that guide the carrier and the in-circuit test fixture in a first substantially horizontal direction. A vertical slider (such as 218) of the loader is attached between the carrier and the mechanism base. The vertical slider includes an actuator (such as 312) that is operable to slide the carrier and the in-circuit test fixture in a second substantially vertical direction between an upper position and a lower position. The horizontal slider and the vertical slider are operable to guide the in-circuit test fixture and the carrier between a receive position, wherein the in-circuit test fixture may be loaded on the carrier, and a test position, wherein a printed circuit board assembly supported by the in-circuit test fixture may be tested. Also, a clamp (such as 380) mounted on a testing base (such as 224) is able to selectively secure the in-circuit test fixture to the testing base in the test position.

[0051] The actuator may include a ram (such as 314) connected to the carrier. Additionally, the loader may include a proximity sensor (such as 390) mounted on the testing base and sensing whether the in-circuit test fixture is in the test position.

[0052] The carrier preferably further includes a pair of tracks (such as 254), with one of the tracks extending along each of the side rails. Rollers (such as 256) may be positioned along the tracks to support the in-circuit test fixture and to aid sliding movement of the in-circuit test fixture along the tracks. The carrier may also include a handlebar (such as 262) between the side rails. The loader may also include a tray lock (such as 298) connected to the mechanism base that selectively engages an aperture in the carrier to lock the carrier in the receive position.

[0053] The clamp preferably includes a body (such as 382) and a pair of arms (such as 384) extending from the body. The clamp is preferably moveable in a spiral motion from an unclamp position, wherein the clamp does not clamp the in-circuit test fixture, to a clamp position, wherein the clamp clamps the in-circuit test fixture to the testing base in the test position. In a preferred embodiment of the present invention, the loader includes a clamp actuator (such as 366) connected to the testing base that is operable to move the clamp spirally between the unclamp position and the clamp position. The clamp actuator preferably includes a ram (such as 368) connected to the clamp, and the ram preferably extends through a plate (such as 344) that is fixed to the base. The clamp holds the in-circuit test fixture between the clamp arms and the support plate in the clamp position.

[0054] Stated another way, an embodiment of the present invention may be described as a method of loading an in-circuit test fixture (such as 212) in an in-circuit test system. The method includes sliding the in-circuit test fixture between side rails (such as 250) of a carrier until the in-circuit test fixture abuts and end rail (such as 252) of the carrier when the carrier is in a receive position, and locking the in-circuit test fixture to the carrier by preventing the in-circuit test fixture from moving away from the end rail. The method further includes sliding the carrier and the in-circuit test fixture horizontally along horizontal guide shafts (such as 286) in a first horizontal direction from the receive position to a match position, and actuating a vertical slider (such as 218) connected to the carrier to slide the in-circuit test fixture vertically along vertical guide shafts (such as 316) in a second vertical direction from the match position to a test position. Finally, the method includes clamping the in-circuit test fixture in the test position.

[0055] The vertical slider step may include actuating a ram (such as 314). Additionally, the method may include sensing that the in-circuit test fixture is in the test position before the step of clamping the in-circuit test fixture in the test position.

[0056] The horizontal sliding step preferably includes manually sliding the carrier, and the clamping step preferably includes moving a clamp (such as 380) in a spiral motion so that the clamp abuts the in-circuit test fixture. The clamping step preferably includes actuating a ram (such as 368).

[0057] Stated yet another way, an embodiment of the present invention may be summarized as an in-circuit test fixture loader (such as 210) that includes a carrier (such as 214), which is able to receive and support an in-circuit test fixture so that the fixture is positioned between opposing side rails (such as 250) of the carrier and the fixture abuts an end rail (such as 252) of the carrier that extends between the side rails. The loader also includes means for sliding the carrier and the in-circuit test fixture between a receive position, wherein the in-circuit test fixture may be loaded on the carrier and unloaded from the carrier, and a test position, wherein a circuit secured to the in-circuit test fixture may be tested, and for selectively locking the in-circuit test fixture in the test position.

[0058] It will be clear that the present invention is well adapted to attain the ends and advantages mentioned as well as those inherent therein. While a presently preferred embodiment has been described for purposes of this disclosure, various changes and modifications may be made which are well within the scope of the present invention. For example, the horizontal slider 216 and the vertical slider 218 could be arranged in a different configuration. Numerous other changes may be made which will readily suggest themselves to those skilled in the art and which are encompassed in the spirit of the invention disclosed and as defined in the appended claims. 

What is claimed is:
 1. An in-circuit test fixture loader, the loader comprising: a carrier operable to receive and support an in-circuit test fixture, the carrier comprising a pair of opposing side rails and an end rail between the side rails, the side rails and the end rail spaced to receive the in-circuit test fixture between the side rails and against the end rail; a fixture lock connected to the carrier operable to selectively abut the in-circuit test fixture to prevent movement of the in-circuit test fixture away from the end rail; a horizontal slider attached between the carrier and a mechanism base comprising guide shafts on opposite sides of the carrier that guide the carrier and the in-circuit test fixture in a first substantially horizontal direction; a vertical slider attached between the carrier and the mechanism base comprising an actuator that is operable to slide the carrier and the in-circuit test fixture in a second substantially vertical direction between an upper position and a lower position, wherein the horizontal slider and the vertical slider are operable to guide the in-circuit test fixture and the carrier between a receive position, wherein the in-circuit test fixture may be loaded on the carrier, and a test position, wherein a printed circuit board assembly supported by the in-circuit test fixture may be tested; and a clamp mounted on a testing base operable to selectively secure the in-circuit test fixture to the testing base in the test position.
 2. The loader of claim 1, wherein the actuator comprises a ram connected to the carrier.
 3. The loader of claim 1, further comprising a proximity sensor mounted on the testing base and sensing whether the in-circuit test fixture is in the test position.
 4. The loader of claim 1, wherein the carrier further comprises a pair of tracks, one of the tracks extending along each of the side rails.
 5. The loader of claim 4, wherein the carrier further comprises rollers positioned along the tracks, the rollers being operable to support the in-circuit test fixture and to aid sliding movement of the in-circuit test fixture along the tracks.
 6. The loader of claim 1, wherein the carrier includes a handlebar between the side rails.
 7. The loader of claim 1, further comprising a tray lock connected to the mechanism base that selectively engages an aperture in the carrier to lock the carrier in the receive position.
 8. The loader of claim 1, wherein the clamp comprises a body and a pair of arms extending from the body, the clamp moveable in a spiral motion from an unclamp position, wherein the clamp does not clamp the in-circuit test fixture, to a clamp position, wherein the clamp clamps the in-circuit test fixture to the testing base in the test position.
 9. The loader of claim 8, further comprising a clamp actuator connected to the testing base that is operable to move the clamp spirally between the unclamp position and the clamp position.
 10. The loader of claim 9, wherein the clamp actuator comprises a ram connected to the clamp.
 11. The loader of claim 10, wherein the ram extends through a plate that is fixed to the base and wherein the clamp holds the in-circuit test fixture between the clamp arms and the support plate in the clamp position.
 12. A method of loading an in-circuit test fixture in an in-circuit test system, the method comprising: sliding the in-circuit test fixture between side rails of a carrier until the in-circuit test fixture abuts and end rail of the carrier when the carrier is in a receive position; locking the in-circuit test fixture to the carrier by preventing the in-circuit test fixture from moving away from the end rail; sliding the carrier and the in-circuit test fixture along horizontal guide shafts in a first horizontal direction from the receive position to a match position; actuating a vertical slider connected to the carrier to slide the in-circuit test fixture along vertical guide shafts in a second vertical direction from the match position to a test position; and clamping the in-circuit test fixture in the test position.
 13. The method of claim 12, wherein the actuating a vertical slider step comprises actuating a ram.
 14. The method of claim 12, further comprising a step of: sensing that the in-circuit test fixture is in the test position before the step of clamping the in-circuit test fixture in the test position.
 15. The method of claim 12, wherein the horizontal sliding step comprises manually sliding the carrier.
 16. The method of claim 12, wherein the clamping step comprises moving a clamp in a spiral motion so that the clamp abuts the in-circuit test fixture.
 17. The method of claim 12, wherein the clamping step comprises actuating a ram.
 18. An in-circuit test fixture loader, the loader comprising: a carrier operable to receive and support an in-circuit test fixture so that the in-circuit test fixture is positioned between opposing side rails of the carrier and the in-circuit test fixture abuts an end rail of the carrier that extends between the side rails; and means for sliding the carrier and the in-circuit test fixture between a receive position, wherein the in-circuit test fixture may be loaded on the carrier and unloaded from the carrier, and a test position, wherein a circuit secured to the in-circuit test fixture may be tested, and for selectively locking the in-circuit test fixture in the test position.
 19. The loader of claim 18, wherein the means for sliding and locking comprises a mechanism connecting the carrier to a base, the mechanism being operable to move the carrier relative to the base between the receive position and the test position.
 20. The loader of claim 19, wherein the mechanism comprises: a horizontal slider that allows the carrier to move substantially horizontally; and a vertical slider that allows the carrier to move substantially vertically.
 21. The loader of claim 18, wherein the carrier is a tray that further comprises tracks extending along the side rails and carrying rollers that are operable to support the in-circuit test fixture. 